It is known that a lack of dopamine in the brain is associated with Parkinson's disease. Dopamine is a chemical messenger (neurotransmitter) in the nervous system and is produced by neural cells directly in the brain. It also is known that a specific molecule, GDNF (Glial-cell line derived neurotrophic factor), can reconstruct the capability of neural cells to produce dopamine. GDNF is approximately a 20 kDa (kilodalton) glycosylated polypeptide and is known to be expressed by cells such as Seritoli cells, type 1 astrocytes, Schwann cells, neurons, pinealocytes, and skeletal muscle cells. The activity of GDNF as a survival factor for dopaminergic neurons suggests the potential use of GDNF in the treatment of Parkinson's disease. Furthermore, GDNF promotes neuron survival, thereby slowing or stopping the progression of Parkinson's disease.
For the treatment of Parkinson's disease, GDNF can be delivered directly to a target region, e.g., a posterior dorsal region of the Putamen, the subthalamic nucleus (STN), etc., or cells expressing GDNF can be delivered to the target region. Alternatively, viral vectors or pure DNA can be a delivered locally to trigger GDNF production.
Methods of administering a drug or other material to a target part of the body are known in the art. For example, U.S. Pat. No. 6,026,316 discloses a method for targeted drug delivery into a living patient using magnetic resonance (MR) imaging. The method uses MR imaging to track the location of drug delivery and estimate the rate of drug delivery. More particularly, an MR-visible drug delivery device is positioned at a target site to deliver a diagnostic or therapeutic drug solution into the tissue. The spatial distribution kinetics of the injected or infused drug agent are monitored quantitatively and non-invasively using water proton directional diffusion MR imaging to establish the efficacy of drug delivery at a targeted location.
U.S. Pat. No. 5,720,720 discloses a method of high-flow microinfusion that provides convection-enhanced delivery of agents into the brain and other solid tissue structures. The method involves positioning the tip of an infusion catheter within a tissue structure, and supplying an agent through the catheter while maintaining a pressure gradient from the tip of the catheter during infusion. The method can be used to deliver various drugs, protein toxins, antibodies for treatment or imaging, proteins in enzyme replacement therapy, growth factors in the treatment of various neurodegenerative disorders and viruses and gene therapy.
U.S. Pat. No. 5,735,814 discloses techniques for infusing drugs into the brain to treat neurodegenerative disorders by an implantable pump and catheter. The drugs are capable of altering the level of excitation of neurons in the brain. A sensor is used to detect an attribute of the nervous system which reflects the hyperexcitation of the nerve cells projecting onto the degenerating nerve cells, and a microprocessor algorithm analyzes the output from the sensor in order to regulate the amount of drug delivered to the brain.
Finally, U.S. Pat. No. 6,549,803 discloses the movement of material in an organism, such as a drug injected into a brain. The movement is modeled by a uniformly structured field of static constants governing transport by moving fluid and diffusion within the fluid. This supports planning of material introduction, (e.g., infusion, perfusion, retroperfusion, injections, etc.) to achieve a desired distribution of the material, continuing real-time feedback as to whether imaged material is moving as planned and will be distributed as desired, and real-time plan modification to improve results.